Anthropometric Measurements of Singleton Live Full-Term Newborns in Comparison to Who Standard at University of Gondar Comprehensive Specialised Hospital, Ethiopia

Abstract Background Anthropometry is a universally applicable, non-expensive, rapid and noninvasive technique used to evaluate and reflect the nutritional status of an individual. Anthropometric measurements of newborns reflect their general health, nutritional status and future survival by tracking trends in growth and development over time. It has also considerable significance in terms of determining the risk of death and extra uterine complications. Most previously conducted studies assessing newborn anthropometry had used birth weight as the sole parameter. But it is apparent that other anthropometric measurements, such as length and head circumference, are also important in predicting short-term and long-term outcomes. So this study assesses anthropometric measurements of singleton live full-term newborns at University of Gondar comprehensive specialised hospital, Ethiopia. Material and methods Hospital-based cross-sectional study was conducted among 333 newborn from 5 June to 11 July 2022, in the maternity and neonatal ward of University of Gondar comprehensive specialised hospital. A systematic random sampling technique was employed to select the study participants. The Kobo toolbox software platform was used for data collection, and STATA software version 16 was used for analysis. Results The mean birth weight, length and head circumference of the newborns in the current study were 2977 grams (95% CI: 2935.7, 3018.3), 47.05 centimeters (95% CI: 46.72–47.37) and 34.7 centimeters (95% CI: 34.6, 34.88), respectively. The prevalence of SGA (< 10th percentile) and LGA (> 90th percentile) was 20.12% and 6.01%, respectively. Independent samples t-test was done to see the association of newborn sex with anthropometric indices, and the result showed that the difference was statistically insignificant in all of anthropometric parameters. Conclusion This study of normal reference values will provide basic step for future standardisation of Ethiopian term newborns anthropometric parameters to be used for accurate assessment of newborns.


Introduction
Anthropology is the study of the origin and development of human societies and cultures; it is translated literally from ancient Greek, the study of humanity [1].Anthropometry in anthropology is usually used to measure various parts of the human body, not only limited to height but the development of the human body is an important concern [2].The term anthropometry also comes from Greek words (Anthropos, "man" and metron, "measurement") to understand human physical variation in various attempts to correlate physical with racial and psychological traits [3,4].It is a universally applicable, non-expensive, rapid and noninvasive technique used to evaluate and reflect the nutritional status of an individual [5,6].Anthropometric measurements of newborns are an important clinical tool used to: determine nutritional status at birth; diagnose abnormally small or large neonates; gauge risks of subsequent poor growth, health, development, and survival throughout infancy; and predict long-term squeal [7,8].Anthropometric studies on children in different countries and regions of a country reflect that changes in children's nutrition and health status are important tools to evaluate social health [9].Typically they are used in the paediatric population to evaluate the general health status, nutritional adequacy, and the growth and developmental pattern of the child.Growth measurements and normal growth patterns are the gold standards by which clinicians assess the health and well-being of a child [10].In adults, body measurements can help to assess health and dietary status and future disease risk.These measurements can also be used to determine body composition in adults to help determine underlying nutritional status and diagnose obesity [11].Newborns are classified based on their birth weight, gestational age (GA), and weight-adjusted for GA to identify high-risk infants, including small for gestational age (SGA) and large for gestational age (LGA), as they mostly need specific interventions [12].Approximately four million global neonatal deaths occur annually, and 98% occur in developing countries [13].Intrauterine growth indicated by birth anthropometry is one detrimental factor for neonatal survival [14].Low birth weight in its self-underlies approximately 80% of all neonatal deaths [15].In many low-income and middle-income countries, the proportion of babies born SGA is generally higher with its associated risk of death during the neonatal and infancy period [16].Beyond infancy, survivors continue at increased risk for the development of coronary heart disease, chronic kidney disease, hypertension and metabolic syndromes; they will also face problems of intellectual, physical and sensory disabilities later in life [17][18][19][20][21].Anthropometric indices commonly used for the assessment of newborns are birth weight, length and head circumference (HC) about GA at birth [22,23].Birth weight is the most widely used anthropometric index of size at birth [3].It does not only indicate the growth, development and newborn survival but is also a valuable indicator of maternal health, nutrition, genetics, socio-economic level, environmental influences and quality of antenatal services [24,25].A newborn's birth length is measured from the top of the head to the bottom of the heel and provides useful information regarding the general condition of the baby and has predictive value for the final adult height [26].Defected fetal linear growth and subnormal newborn length are major predictors of early infant linear growth failure [27].It has been also implicated that there is a relationship between birth length and risk of hospitalisation [28].HC is another important indicator of newborn body size, which provides important diagnostic and prognostic information in addition to that given by birth weight and length [29], and it is a well-established birth dimension and an important screening procedure for detecting abnormalities in head growth [29,30].It is also strongly correlated with length at birth, later in infancy and early childhood [31], as well as correlated with mental power and school performance throughout early school-age years [32,33].It is used to assess their development and, in some instances, can be an indicator of chronic malnutrition [34].Many studies underlined the need for anthropometric ranges for birth weight, length and HC specific to given countries by considering the impact of ethnicity, race and sex.The World Health Organization (WHO) gave great attention to sex and race in terms of ethnicity and geographical distribution as major factors to be considered when developing appropriate reference standards.This is why in 2006 the WHO readjusted its growth charts and anthropometric standards supposed to apply to both developing and developed countries [8,35,36].Even though the WHO advises a single international growth standard for developed and developing countries, it is ideal to establish local national growth charts reflecting each country's genetic characteristics and prepared according to the features outlined by the WHO [24,37].In Ethiopia, there is a scarcity of data regarding anthropometric measurements of term newborn, so this study was proposed.

Study period and setting
The study was conducted from 5 June to 11 July 2022, at UoGCSH, which is located in Gondar town, one of the administrative zones of Amhara regional state, Northwest Ethiopia.UoGCSH is a referral hospital in northwest parts of the Amhara region, serving as a teaching hospital for the College of Medicine and Health Sciences, University of Gondar, and a referral centre for more than twelve districts, with a catchment population of five to seven million.

Study design
The hospital-based cross-sectional study design was conducted.

Source population
All singleton term live newborns in the maternity and neonatal ward of UoGCSH were our source population.

Study population
All singleton term live newborns in the maternity and neonatal ward of UoGCSH during our study period.

Inclusion criteria
Newborns, who are full-term, singleton, and alive

Exclusion criteria
Newborns admitted to the neonatal intensive care unit, who had a gross congenital anomaly, and who had caput succedaneum and/or cephalohematoma were excluded from the study.

Definition of terms
 Term newborn: a baby that was born between 37 weeks 0 days and 40 weeks 6 days [38]. SGA: Birth weight less than 10 th percentile for a newborn at that gestational age [24]. Appropriate for gestational age (AGA): Birth weight ranges from 10 th Percentile to 90 th percentile relative to other newborn's born at that gestation age [24]. LGA: birth weight greater than the 90 th percentile at that specific gestational age, also known as fetal macrosomia [24].

Data collection tools and techniques
Electronic-based questionnaires were developed after reviewing relevant works of literature to include all the possible variables that address the objective of this study.Firstly, the questionnaire was developed in English and translated into the local language (Amharic), and finally retranslated into English.
The questionnaire was prepared in the kobo toolbox platform.Then the prepared form was uploaded on the mobile phone of the data collector application (ODK) tool.Three qualified and trained midwifery nurses collect the data by measuring anthropometric indices of the newborn (weight, length and HC) by following the WHO's standardised measuring protocol.The principal investigators assisted and coordinated the overall data collection process.

Anthropometry of the newborn
The newborn birth weight was measured using a digital electronic baby weighing scale after being checked for zero adjustments without any clothing and recorded to the nearest 10 gm.A non-stretchable plastic measuring tape meter was applied anteriorly just above the eyebrows (glabella) and posteriorly at occipital protuberance to measure the HC of the newborn and recorded to the nearest millimeter.The newborn's crown heel length was measured by putting the baby on a flat surface, one assistant measurer positioned the head and the chest at Frankfort vertical position, and the lead measurer gently pressed the newborn's knee with the left hand and marked the point where the heel and the crown touched the surface by his/her right hand, then the newborn was taken off and the distance between the two marked points was measured using a non-stretchable tape meter to the nearest millimeter (Figure 1).

Data processing and analysis
After completing each questionnaire, the data collectors upload the data to our created kobo toolbox server.Then the principal investigator checked all of the data for completeness, missed value and consistency.Finally, the data was downloaded from the system in CSV format and exported to STATA software version 16 for analysis.Independent samples t-test was conducted to compare the mean anthropometric indices among sex.T and F statistics were calculated and p ≤ 0.05 was taken as statistically significant.Finally, the result was presented in the form of texts, tables and diagrams.

Data quality control and management
An internal pilot study was conducted on 35 newborns.Data collectors were trained and collected under the supervision of the principal investigator and one paediatrician.The collected data was reviewed and observed by the investigator for its completeness, and incomplete data were deleted from the system.Outlier observation was diagnosed and adjusted before commencing the statistical analysis.

Newborn characteristics
A total of 333 newborns were included for the anthropometric measurements, among which 168 (50.45%) were females and 165 (49.55%) were males.The mean birth weight, length and HC of the newborn were 2977 grams, 47.05 cm and 34.7 cm, respectively.The prevalence of SGA (< 10th percentile) and LGA (> 90 th percentile) was 20.12% and 6.01%, respectively.Independent samples t-test was done to see the association of newborn sex with birth weight, length, and HC.The analysis showed that the mean difference in birth weight, length and HC between males and females was 13 gm, 0.45 cm and 0.28 cm, respectively (male > female), but the difference was statistically insignificant (p > 0.05) in all of the three anthropometric parameters.The mean GA at birth for males was lower than that of females (Table 1).

Term newborn anthropometric measurements by GA and sex
There was a gradual increase in the mean values of all term newborn anthropometric measurements (birth weight, length and HC) of both sexes from 37 to 42 weeks GA, except the mean birth weight at GA = 40 weeks was somewhat less than the mean birth weight at GA = 39 week, mean HC at GA-42 < mean at GA-41, and mean length at GA-39 < at GA-38.But the difference was statistically insignificant with the clustering of higher newborn numbers (99) at 37 weeks of GA and minimum numbers (19) at 42 weeks of GA (Table 2).
The mean birth weight, length and HC of newborns at all GA weeks revealed that there are no statistically significant differences between males and females at all GA (P > 0.05).
The detail is provided in Table 3.
Plotting birth weights for boys and girls of our term newborns against the WHO MGRS international percentile curves would generally overestimate the values at all percentiles (1 st , 3 rd , 5 th , 15 th , 25 th , 50 th , 75 th , 85 th , 95th, 97 th and 99 th percentiles) as illustrated in Figures 2 and 3 below.
Although the values for females crown heel length of our sample at the 75 th and 95 th percentile were similar to values from the WHO's MGRS, plotting crown heel length for both boys and girls against this international standard curves would generally overestimate crown heel length below the GA-gestational age, SD-standard deviation, HC-head circumference.          4 and 5).
The HC percentiles were comparable with the WHO's MGRS below the 25 th percentile but above the 25 th percentile, our values were consistently greater than the WHO's MGRS standard in both sexes as shown in Figures 6 and 7 below.

The relationship between newborn and maternal anthropometry
Correlational analysis was done to see the association between maternal anthropometric parameters [weight, height, mid-upper arm circumference (MUAC), body mass index (BMI) and lean body mass (LBM)] and newborn anthropometric indices (birth weight, HC and length).As a result, clear associations between maternal and newborn anthropometric parameters were observed.
Moderately strong associations (0.3 > r < 0.5) were found in newborn birth weight with maternal weight, MUAC, and LBM with a Pearson correlation coefficient (r) of 0.36, 0.37 and 0.36, respectively.Maternal height and BMI had also a weak positive correlation with birth weight.The newborn length has a moderate positive correlation with maternal MUAC and LBM.
In addition, maternal BMI, weight and height have also a weak positive correlation with newborn length.All of the maternal anthropometric parameters (weight, height, MUAC, LBM and BMI) has a statistically significant (p < 0.05), but weakly positive correlation (r < 0.3) with newborn HC (Table 4).But maternal anthropometric parameters were strongly related to each other (e.g.maternal weight and BMI, r = 0.846; maternal weight and MUAC, r = 0.7926; maternal weight and LBM, r = 0.9139; maternal LBM and height, r = 0.7014), which may hamper the interpretation of the independent correlation.

Discussion
This study attempted to assess the anthropometric measurements of term live singleton newborns at UoGCSH.The mean birth weight in this study was observed to be lower than that of studies conducted in England (3272 gm.) [39], Turkey (3334 gm.) [24] and Egypt (3350 gm.) [40].This discrepancy may be due to the geographical location, racial and environmental factors as they are responsible for the differences in growth and body size.And the mean birth weight in our study was comparable to studies conducted in Sudan (3040 gm.) [41] and Yemen (3113 gm.) [36].This similarity may be explained by comparable socio-demographic status, as Sudan, Yemen and Ethiopia are developing countries in Africa in which they may have approximate health care, nutritional status and genetic similarity.But our mean birth weight was higher than a mean value of studies conducted in Bangladesh (2770 gm) [42], and Himachal Pradesh, India (2900 gm).This may be due to difference in food habits, lifestyle, socio-cultural trend, ethnicity and geographical distribution.
The mean term newborn length in this study was lower than that of studies conducted in England (50.8 cm) [39], Turkey (48.3 cm) [24], Bangladesh (49.4) [42], India (49.12 cm) [3] and Egypt (49.4 cm) [40], but it was comparable with Sudanese newborn length (47.4 cm) [41].This discrepancy may be explained by the fact that the composition and body growth difference is attributable to the difference in rates of growth, ethnicity, gestational age and maternal nutritional status.However, our mean HC value was higher than studies conducted in Yemen (33.7 cm) [36], England (34.1 cm) [39] and Himalaya (33.49 cm) [3], but it was similar to Sudanese (34.9 cm) [41] and Egyptian (34.5) [40] newborns HC.This varying difference in HC of our newborns from different countries may be explained by size difference is attributable to the difference in rates of growth, gestational age, sociocultural trend, ethnicity, socio-economic and geographical location.Moreover, this further demonstrates the racespecific differences in anthropometric parameters as genetic differences exist among races regarding growth and body composition [24,43].When comparing the mean values of the birth weight, HC, and length in our study with those from the WHO Multicenter Growth Reference Study (MGRS) [44], the difference was statistically significant for all three parameters.In both sexes, mean birth weight and crown heel length were statistically smaller than the WHO's MGRS.This may be explained by the fact that the included newborns in the WHO study were recruited from few selected countries, which are not necessarily representing all nations, and this international growth standard had exclusion criteria of mothers living at an altitude greater than 1600 m, but the current study area has altitudes greater than 1600 m, which might influence newborn birth size.So the need for specific anthropometric standards for those who live at higher altitudes might be a question worth investigating.
Regarding our mean HC value, it was greater than this international average.These findings of higher HC value in comparison with MGRS is supported by a study conducted in Ethiopia previously by Ephrem et al [45], in which they reported that Ethiopian HC measurement is considerably higher than those of the WHO standard.This could be due to a genetic difference or environmental factors influencing the HC, and it may indicate the need for a population-specific chart for assessing and interpreting HC measurements of Ethiopian newborns.When comparing the mean values of the birth weight, HC and length in our study with those from the WHO Multicenter Growth Reference Study (MGRS) [44], the difference was statistically significant for all three parameters.In both sexes, mean birth weight and crown heel length were statistically smaller than the WHO's MGRS.This may be explained by the fact that the included newborns in the WHO study were recruited from few selected countries, which are not necessarily representing all nations.This international growth standard had exclusion criteria of mothers living at an altitude greater than 1600 m, but the current study area has altitudes greater than 1600 m, which might influence newborn birth size.So the need for specific anthropometric standards for those who live at higher altitudes might be a question worth investigating.
Regarding our mean HC value, it was greater than this international average.These findings of higher HC value in comparison with MGRS is supported by a study conducted in Ethiopia previously by Ephrem et al [45], in which they reported that Ethiopian HC measurement is considerably higher than those of the WHO standard.This could be due to a genetic difference or environmental factors influencing the HC, and it may indicate the need for a population-specific chart for assessing and interpreting HC measurements of Ethiopian newborns.

Conclusion
The means of newborn birth weight, HC and length in our study were comparable with Sudan, Egypt and Yemen but showed a significant variation when compared to different Western countries.This study of normal reference values will provide basic step for future standardisation of Ethiopian term newborns anthropometric parameters to be used for accurate assessment, development and maturity of newborn births that would lead to identify newborns at risk and help in better management.

Figure 1 .
Figure 1.Sketching of length measurement technique used during data collection.

Figure 2 .
Figure 2. Comparison of current study birth weight percentile value with the WHO's MGRS for boy newborns in UoGCSH, Northwest Ethiopia, 2022.

Figure 3 .
Figure 3.Comparison of current study birth weight percentile value with the WHO's MGRS for girl newborns in UoGCSH, Northwest Ethiopia, 2022.

Figure 4 .
Figure 4. Comparison of current study length percentile value with the WHO's MGRS for boy newborns in UoGCSH, Northwest Ethiopia, 2022.

Figure 5 .
Figure 5.Comparison of current study length percentile value with the WHO's MGRS for girl newborns in UoGCSH, Northwest Ethiopia, 2022.

Figure 6 .
Figure 6.Comparison of current study HC percentile value with the WHO's MGRS for boy newborns in UoGCSH, Northwest Ethiopia, 2022.

Figure 7 .
Figure 7.Comparison of current study HC percentile value with the WHO's MGRS for girl newborns in UoGCSH, Northwest Ethiopia, 2022.

Table 2 .
GA specific mean ± SD value of birth weight, length and HC of term newborns (both sex), in the UOGCSH, Northwest Ethiopia, 2022 (n = 333).

Table 3 .
Pairwise comparison of mean birth weight, length and HC between female and male term newborns at different GA with its statistical significance in UoGCSH, Northwest Ethiopia (n = 333).

Table 5 .
Birth weight, length and HC percentiles values for term newborn in the UoGCSH, Northwest Ethiopia, 2022 (n = 333).